That'll help nicely

American Express has long used celebrities to promote its credit cards, but when Bono endorsed its latest offering yesterday it was obvious there was something different about it.

Instead of offering cashback to customers, like Amex's Platinum and Blue credit cards, Amex RED has been designed to help people give as they spend, with money going to the fight against HIV and Aids in Africa.

For every £1 spent on the card, Amex will donate 1% to the Global Fund, and if you spend more than £5,000 a year on the card the donation will increase to 1.25%. This is more than cashback customers receive if they have either of the company's other cards. There is also a one-off payment of £5 to charity made if the card is used within the first month of being issued.

The card is aimed at what Amex describes as "conscience consumers", people who buy fair-trade and ethical products but want to go further and use their spending to affect social change. Research by the Future Laboratory suggests there are currently 1.5 million conscience consumers in the UK, where the card will makes it first appearance on March 1, and their number is expected reach 3.9 million by 2009.

The card, which is part of a wider initiative called Product RED involving companies such as Gap and Armani, has been billed by Amex as the first to meet the needs of these consumers.

But it's not the only charity card on the market, so what do they mean? "Existing charity cards are more of a niche product while we see this appealing to a larger market," said Amex spokesman Doug Smith. "This is for people who are looking for a card that says something about them but also does some good at the end of the day."

A far more tangible difference is that the card also offers customer benefits, including the REDdeals programme - which offers exclusive offers on tickets among other things - and the REDpass competition. This offers one cardholder a month the chance to win "the opportunity to do something bespoke and extraordinary", with prizes designed to appeal to cardholders. The first month's prize will be a trip to South Africa to meet an artist and receive a one-off artwork.

"Any card that is linked to a cause has to work for the customer as well as the charity or it won't be taken up and it won't make any money," Mr Smith said.

These perks aren't at the expense of what the charity receives. According to financial information company Moneyfacts, the ongoing payments from the RED card outstrip those made by other issuers, which tend to offer between 0.25% and 0.5% of the spend.

Other cards do offer larger upfront payments - for example, Halifax's cards for Cancer Relief and the NSPCC pay £20 to the respective charities on first use - but as Moneyfacts' researcher Samantha Owens says: "The card is not designed just to be opened" but to be used.

Even big spends on the card won't generate a massive amount of money - for example if you spent £6,000 on the card over a year, qualifying you for the 1.25% payment, the amount given to charity would be just £75, plus the opening £5. But if you pay off your balance every month then this donation doesn't cost you a penny, and any money going to a good cause has got to be better than nothing.

Particularly as nothing is what a lot of people give if left to their own devices, according to research by Amex which showed 31% of consumers felt they wanted to support good causes but without spending any extra time or money to do so.

"People can give money as they spend, they're not having to hive off additional money and there's an ease factor because they don't have to organise the donation," said Mr Smith.

According to Ms Owens, you won't be paying over the odds for this convenience. The card offers an APR of 12.9%. This compares unfavourably with other opening deals - the Sainsbury's Visa card, for example, offers 0% on purchases for the first 10 months - but it is lower than the standard APR most cards revert to after the opening offer period. These tend to be around 15.9-16.9%.

The balance transfer rate of 5.9% for the life of the balance can also be beaten by 0% deals elsewhere, but card issuers are increasingly including transfer fees of up to 2% on those deals. "A lot of providers are moving towards 'life of the balance' rates and 5.9% is one of the lowest rates for that," Ms Owens said. The terms and conditions on the card are pretty standard and elements like the purchase protection that it offers aren't available on all cards. "The charity element aside, this is on the better side of credit cards," she said.